CVE-2011-2626 in Web Browser
Summary
by MITRE
Opera before 11.50 allows remote attackers to cause a denial of service (application crash) by using "injected script" to set the SRC attribute of an IFRAME element.
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Analysis
by VulDB Data Team • 11/13/2021
The vulnerability described in CVE-2011-2626 represents a denial of service flaw affecting Opera web browsers prior to version 11.50. This security issue stems from improper handling of HTML elements when malicious scripts attempt to manipulate iframe source attributes, creating conditions that lead to application instability and potential crashes. The flaw specifically manifests when an attacker injects malicious script code that targets the src attribute of iframe elements, exploiting a weakness in Opera's HTML parsing and rendering mechanisms. This vulnerability falls under the category of input validation and sanitization failures, where the browser fails to properly validate or sanitize user-provided content before processing it as part of the document structure.
The technical implementation of this vulnerability involves the manipulation of iframe elements through script injection techniques that alter the src attribute in ways that Opera's rendering engine cannot properly handle. When the browser encounters such malformed or maliciously constructed iframe elements, it fails to properly process the source attribute, leading to memory corruption or unexpected execution paths that ultimately result in application termination. The flaw demonstrates a classic case of inadequate boundary checking and input sanitization, where the browser does not properly validate the contents of the src attribute before attempting to load or render the referenced content. This type of vulnerability is particularly concerning as it can be triggered through simple web page content manipulation without requiring complex attack vectors or user interaction beyond visiting a malicious webpage.
From an operational impact perspective, this vulnerability presents significant risks to users of affected Opera versions, as it allows remote attackers to cause arbitrary application crashes simply by crafting malicious web content. The denial of service condition affects the browser's stability and usability, potentially disrupting user workflows and creating opportunities for more sophisticated attacks if combined with other vulnerabilities. Attackers could leverage this flaw to repeatedly crash browser sessions, making web browsing unreliable and potentially disruptive to productivity. The vulnerability also demonstrates the importance of proper HTML element handling in web browsers, as iframe elements are commonly used components in web applications, making this flaw particularly dangerous in environments where users may encounter malicious content. This issue aligns with CWE-129, which addresses improper validation of input boundaries, and represents a clear example of how inadequate input sanitization can lead to application instability and denial of service conditions.
The mitigation strategies for CVE-2011-2626 primarily focus on updating to Opera version 11.50 or later, which includes fixes for the iframe source attribute handling. Users should also implement proper web filtering and content security policies to prevent exposure to malicious web content. Security administrators should ensure that all Opera installations are kept current with the latest security patches and updates. Additional protective measures include implementing browser security extensions, configuring content filtering systems, and educating users about the risks of visiting untrusted websites. This vulnerability also highlights the importance of regular security assessments and vulnerability management processes to identify and remediate similar issues before they can be exploited in the wild. Organizations should consider implementing automated patch management systems to ensure timely deployment of security updates across all browser installations. The ATT&CK framework categorizes this vulnerability under the 'Execution' phase, specifically related to 'Command and Scripting Interpreter' techniques, where attackers leverage browser vulnerabilities to execute malicious code that results in system instability and denial of service conditions.